Andrew m



(No Model.)

A. M. COYLE. ELEGTRI SWITGH.

P tented Mar. 14, 1893.

2 Sheets-Sheet 1.

lll/mmm Liu/mm (No Model.) 2 Sheets-Sheet 2.

A. M. COYLE. ELBCTRIC SWITGH.

No. 4935185. Patented Mar. 14. 1893.

? %amb/744 UNITED STATES PATENT OFFICE.

ANDREW M. COYLE, OF BALTIMORE, MARYLAND, ASSIGNOR TO THE STAND- ARDSCREVV ELEVATOR MANUFAOTURING COMPANY, OF SAME PLACE.

ELECTRIC SWITCH.

SPECIFICATION forming part of Letters Patent No. 493,485, dated March14, 1893.

Application filed March 3, 1892. Serial No. &23,600 (No model.)

To all whom it may concern:

Be it known that I, ANDREW M. COYLE, reresiding at Baltimore, Maryland,have invented a new and useful Improvement in Electric Switches, whichimprovement is fully set forth in the following specification.

The present invention relates to electrical switch mechanism designedfor making, breaking and reversing the connections of an roelectro-motor with its supply circuit. The api paratus is particularlycontrived for use in connection With electrically driven elevatorsystems, in which the movable part of the switch is actuated by a pullcord from the car of the elevator.

The switch consists of a movable part or slide carrying spring contactsor brushes, adapted to make contact with a series of terminal plates, towhich are connected resistances in such manner that, as the switch ismoved from its neutral position in either direction, it first makescontact between the main line and the motor through all the resistances,and as itprogresses cuts out the resistances seriat'm.

It frequently happens in Operating switches from the pull cord of anelevator, that the sliding contact or brush is left in such position asto produce an arc, which results in the burning out of the brushes. Toavoid this I provide a retarding or stop mechanism which arrests theswitch just before making the con` tact to switch in the motor; duringwhich arrest the pulling of the cord compresses a spring untilthe latteraccumulates sutticient force to overcome the opposition of the stop, andwhen this occurs the switch is impelled with a quick movement past thedividing line. This mechanism may be of various sorts, and the preferredConstruction will be hereafter described in detail.

The apparatus as a whole is specially contrived with a view topreventing inj ury to the motor by abruptly throwing the current intothe armature coils while the motor is at rest, or by a sudden reversalof its connections with the main circuit to reverse the direction oftravel of the car, elevator attendants being accustomed to make quickmovements of their 5c controlling device. This object is effected firstby the arrangement of the resistances as above indicated, secondly bythe action of the retarding mechanism, thirdly by giving to the slidingswitch a long path of movement, so that the circuit changes effectedthereby are 5 5 made deliberately; and finally by a dash-pot arrangedinconnection with one of the sheaves over which the pull cord passes.

In the acconpanying drawings which form part of this specification,Figure I represents in front elevation a simple form of switch mechanisnconstructed in accordance with the invention, Fig. II, a diagramillustrating the electrical connections and circuits; and Fig. III is adetail view showing the arrangement of the dash pot.

A represents the slide or movable part ot' the switch or circuitchanger. It is suitably mounted and supported in a case or frame B, sothat by means of pull cords A' A it can be moved in either direction.The slide has on each side, and insulated from each other, a bent springcontact or brush a' a. These slide over, making electrical contact with,a series of fixed Contacts, as hereinafter de- 7 5 scribed. The directconductor 4 and return conductor 5 of the main supply circuit areconnected with the brushes a' and a respectively. The actuating cords A'A are connected respectively to opposite ends of a rod A passing looselythrough the body of the slide, and around the rod A at top and bottomare helical springs A A so that the motion of the rod in eitherdirection with respect to the slide is resisted by one of these springs.On the face of the slide are two bell-crank levers C' 0 each terminatingin a hook or tooth at one end, which hook is pressed by a light spring cbeyond the body of the slide. These levers constitute catches which whenengaged by one of the stops D D' D D will check and arrest the slide.When this occurs, the slide will remain stationary while a continuedpull on the cord A' or A will draw rod A len'gthwise of the slidegradually compressing the spring A or A as the case may be. Rod A hastwo cross pinsa t which proj ect through Slots in the face of the slide,and when the rod A is drawn far enough in one direction or the other,one of these pins will IOO strike the tail of lever C or 0 withdraw thetooth thereof, and thus permit the slide to 'explained by reference toFig. II.

advance. As soon as the catch is withdrawn, the energy of the compressedspring Will throw the slide forward for a considerable distance, andthese catches and stops being properly arranged, it is obvious that theslide cannot under any circumstances come to rest at such points aswould cause the current to form an arc.

The stops D D' and D D are arranged in pairs as shown, and are curved onone side so that they engage the tooth of the adjacent catch, when theslide is moving in one direction, and simply push the catch back againstthe prcssure of spring c, when the slide moves in the other direction.

The contact plates before referred to, and the electrical connectionsthereof, will be best On the right of the slideway beginning at. the topare seven separate plates E' to E inclusive, and opposite these is asingle strip F,whose length equals the combined lengths of the oppositeseries of plates. At the lower end of the slideway are seven plates G'to G inclusive, corresponding to the series E' &(3., but placed on theleft of the slideway. Opposite these is a long strip I-I, correspondingto strip F. Plate E' is connected by wire 11, with the correr spondingplate G'. E is similarly connected by wire 12 with G and so onthroughout the series. The long strip F is connected by wire 18 withstrip H. From wire 11 a wire 19 leads to one pole of the motor I, andfrom wire 18 a wire 20 leads to the other pole of the motor. Between theupper and lower series of strips or plates, are the strips K K' whichhave no electrical connections. Conscquently when the brushes connectedwith the slide are in contact with these strips, the motor will bedisconnected. The short plates are the terminals of the resistances L L&e of which six are shown; but obviously the number of resistances, andconsequently the number of terminal plates, could be increased ordiminished as may be desirable for the object in view.

For the purpose of explaining the circuit connections, let it besupposed that the operator has drawn the slide upward from theintermediate or neutral position, until its -brush a' makes contact withplate E its oppoquently at the first motion of slide A to start themotor the current passes through the whole series of resistances, and byfollowing the circuit connections, as shown on the drawings, it will beclearly seen that as the slide continues its upward movement theresistances are cut out, one by one, until the brush a' rests onterminal plate: E', which directly connects with the motor, shutting outall the resistances. Conversely, if the slide be moved downward from theneutral position, it will at first connect the motor in circuit throughall the resistances; but in this case the connection of the motor withthe supply-circuit will be reversed, for the reason that the resistanceterminal plates G' G &e are on the opposite side of the slideway fromthe corresponding plates E' E &a

The retarding stops D' D are placed near the line of separation betweenthe neutral strips K K' and the upper series of terminal plates, whilethe stops D D are placed near the line of separation between theseneutral strips and the lower terminal plates. They act, as alreadyexplained, so that in whatever direction the slide is moved, it ischecked as it approaches these lines ot' separation, and held whileenergy is being stored up in one of the springs A or A sufficient tocarry the brushes or contacts entirely over the line ot' separation, andprevent their coming to rest in such proxinity to the plates E F or G Has would cause the formation of an arc.

It will be observed that, when the motor is running at full speed in onedirection, to cause its reverse movement at full speed the slide musttravel from one end of the slideway to the other; and moreover that inthis movement it Will be twice arrested by the retarding devices. Theseprovisions are found to act efficiently as a means to prevent damage tothe motor by abrupt reversal of its circuit connections. This result isfurther insured by the arrangement shown in Fig. III, in which Mrepresents one of the sleeves under which the pull-cord A passes on itsway to the slide A. On the aXis of this sleeve is a pinion N whichengages a toothed rack O formed in the piston rod of the dash pot P, thepiston Q has a small aperture q through which the fluid (liquid or air)passes as the piston moves up and down. This arrangement prevents anysudden movement being given to the slide.

Having now fully described my said invention, what I claim, and desireto secure by Letters Patent, is

1. In combination with an electrio motor, switch mechanism for making,breaking and reversin g the circuit connections thereof, such mechanismcomprising a slideway having on one side contact plates connectedthrough resistances with one pole of the motor and opposite these asingle plate connected with the other pole, a second series of plateselectrically connected with said resistances but arranged on theopposite side of the slideway from the first series, a complementarysingle contact plate opposite the second series, and a slide carryingbrushes adapted to make contact with said plates, said brushes beingconnected respectively with the direct and return wire of thesupply-circuit, substantially as de scribed.

IOO

IIO

2. An electric switch mechanism comprising in combination, a slidecarrying brushes connected respectively with the two conductors of thesupply or main circuit, a slideway in which said slide is adapted tomove, a series of resistances, a series of terminal plates in saidslideway with which said resistances are electrically connected, asecond series of terminai plates arranged in said slideway on the sideopposite to the first and connected each With one of the first series,the two series being separated by a space of greater length than said.slide, so that as said slide is moved from its intermediate position ineither direction it completes the main circuit first through all theresistances and outs these out one by one as it approaches the extremityof its path,

substantially as described.

3. In an eleetric switch mechanisn, the combination With an electriccircuit, of a movable part or slide carrying contact springs or brushes,and fixed contact piates for completing said circuit through saidsprings or brushes, a stop or detent in the path of said slide, a catchcarried by the latter and engaged by said stop when the slide approachesthe end of one of said plates, a spring through which the power to movesaid slide is appiied, and means for disengaging said catch from saidstop when said spring is compressed to a certain degree, substantiallyas described.

4. In an electric switch mechanism the combination of the slide carryingbrushes for making contact With fixed terminal plates, a cord fordrawing said slide in either direction, springs through which the pullof said cord is transmitted to said slide, stops on opposite sides ofsaid slideway and adjacent to the ends of said contact plates, catches,one on each side of said slide and adapted to be engaged by said stops,and pins acting to disengage said catches and release the slide, so thatthe latter receives an impulse from the energy stored in one of thesprings during the period of arrest, substantially as described.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

ANDREW M. COYLE.

Titnessesz NELSON HISS, CHARLES W. FOWLER.

